//
// Created by Administrator on 2021/11/16.
// 根据输入的半径值，求圆面积

#include <iostream>
using namespace std;

int main()
{
    float radius;
    cout << "Enter Radius of Circle:";
    cin >> radius;
    cout << "The area of circle is: " << 3.1415926 * radius * radius << endl;
}